Happy new year to everyone

Simple explanation is sometimes the most likely, if sample had one tiny bubble of air inside it would radon would escape at lab when tech opened the bottle to take sample for examination. I always do duplicate or triplicate sampling and all labs are not equal in testing for radon in water. It is not worth my expenses for having to go back for free when I hit a weird sample result. That said you probably do many more tests than I do. As I tend to be more expensive because of my testing protocols.

Bruce and Doug: Hi my old friends! Their are now over 15 municipalities in Ontario that are or have implemented a version of the Guelph interpretation of Ontario Building Code. They are even requiring large commercial builds HVAC engineers to state how they are preventing Radon from entering the building.It is resulting in at least developers are reaching out to radon mitigation companies for quotes. Not nirvana but it is a positive change.

The plumber may only need about 1 1/2" for the trap under each tub on commercial sites IE multi story they now do not creaet a box out to gravel they insert a 2" piece of blue foam for tub outs at finished level of the floor.

Talk to Gunnar or Matt at Obar Systems 1 800 949 6227 has some great low cost systems that we use for commercial projects, they are really knowlegable and helpful. tell Bob sent you.

i have to chime in on this one,
#1 i think the idea of checking concrete is a good one simple to do and it eliminates a source if it is negative.
#2 You still have pathways into building if you are having high levels of radon and it is not emanation
smoke test may locate those openings fairly easily big smoke machine may be required.
#3 What is subslab pressure, is this normal for your area? is it bouncing a 24 hr 7day charting may tell you something significant.
#4 Do you have block walls that can be chimneying radon into space i have only had to do this once but when we were stumped, we grab sampled the block and it was super hot. When we tapped block with a branch from each of 4 suction points near the walls (we had 10 suction points by then) it solved the problem.
good luck!

I don't know how to admit this but i missed this whole discussion as it came forward. As another Canadian mitigator who was originally trained and certified as a NRPP mitigator (Dallas taught my first class for measurement certification) , change driven by science is the best .
As part of the team that helped to start CARST supported by AARST in so many ways we owe you in the US big time.
That does not mean that the child does not hold different opinions than the parent, i had initially told Rob Mahoney, back in 2007, that i did not see a time where my company would support a rim wall discharge.... today 99% of our fans are indoors and discharge through rim joist. 90% of our fans are 20 watt fans with radon reductions into the below 1 pCi/l many of these fans operating in the 5 watt of power usage.
Colin has become a radon mitigation leader in Canada and around the world, and it was his class at a CARST convention that i saw the science of communication testing and fan sizing, I could not believe how simple it was. We do it every time now and get our clients to help. They love that we demonstrate the science we use to size their fan. It is now a science that they believe in, they believe in us as a radon mitigator, and they have a reason beyond price to tell their friends to choose us.

Let's pretend for a minute that you want to make the most amount of money you can on a radon mitigation ( i know i do).
Lets compare two teams team 1 shows up in slovenly clothed, rusty van with dusty tools shop vac that is the same as the one in the garage. Team two shows up in a wrapped or lettered Van, wearing uniform that while and it has some glue drips or caulking on it is clean and they use a drop cloth shiny metal shop vac and spend 5 min bringing in their tools in tool boxes and the first thing they do is ventilate to protect from high levels of radon exposure to the workers. do you care what the second team is charging ? My clients don't. We show them the science as we are doing it... if they are interested...most are. What are they going to tell their neighbours? Are they going to keep high radon (their dirty little secret) or are they going to tell their neighbours?
# 1 tool - Radonaway's little red grab sampler GM-1.. sub slab radon is typically 10-100 times the radon in the house... even if they dislike their next door they do not want them to die they tell them ..... I get another job
if you as a mitigator( or your team ) show up in track pants and running shoes with the same tools as the homeowner has, don't ventilate to protect your worker from radon exposure and don't do communication work to prove you are a skilled trade you are maybe you only deserve what you are getting for your work.
i apologize for my rant but low priced competition bugs me.
i started out to write this post to encourage you to attend Colin's seminar at ARRST and if you want to get on his good side and maybe want him to train at your local areas talk about the fishing in your local area's I got him onto fishing for small mouth and largemouth bass this summer at a northern Ontario pickerel/pike lodge, and he cannot wait to do more, ask him about sturgeon fishing in BC ( he landed one over seven feet!!)
Bob W

John you hit the nail squarely on the head. Basic safety is to 1/ remove contaminate at source 2/ remove it along the pathway 3/ use personal protective equipment to protect the worker.
I don't understand why when number 1 is usually the cheapest path even in commercial buildings long term that people go looking at alternative more expensive less reliable options.
Our workplace safety people here in Ontario have consistently said that they want a people proof solution. i.e. it cannot be solved using outdoor air in HVAC system, unless it is with fixed dilution not a variable dilution because in the next year when building operation costs go up someone will change the program to save money. Now i can see in a military base where there is chain of command and penalties for disobeying direct written orders and a sub slab is very expensive and filtering or bringing in outside air is cheap yes go for it but in a building like a school or office where competition for scarce dollars is high it is not a good solution.
It is not rocket science people! it is just nuclear science and building science put together.

I would think that air movement would be more likely to cause plate out on walls and floors, especially if floors were carpeted ( more surface area on carpet fibers than wood or tile floor). back to subject that started all this....... i think the marketing material of filtration system is deceptive and untrue. but anyone who is manufacturing out of country and selling into North American market is unlikely to care.

it would become very difficult to dispose of as well

The other side of a carbon based capture system is that it will build up with lead 210 and all the other short lived radon daughters (progeny for all you proper people) giving off gamma every time there was a radioactive decay the vessel holding the carbon may become a larger heath risk, from gamma exposure, than the radon health risk from alpha energies.

Kevin I think i agree with what your previous post has said. Let me try to say this in a less precise way.
Hepa filters do not (in my opinion) reduce radon in the air i believe that the radon atom is to small to be trapped by the filter media. What it does do is catch the airborne particles that radon daughters would attach to thereby raising the unattached fraction in the air of radon daughters leading to higher health risk ( more unattached fraction to be breathed in that could attach to airway or lung)
i cannot point to a research paper that can prove this hypothesis, but if not it would make for a great thesis topic.

Doug and All: I agree completely that public expectations of cost must be continually updated, it must be very frustrating to hear on a repeated basis.......... but I read on the internet that SSD systems cost only $ 800.00.
About the side wall discharges and fans indoors that we do in Canada. I would agree that this is a model that cold climates may want to look at in code and can be easily codified by using ASHRAE climate zones such as this map https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.iaqsource.com%2Farticle.php%2Fashrae-climate-zone-map%2F%3Fid%3D194&psig=AOvVaw2oZX55PjIFZmiKiuoYFPKS&ust=1614436802821000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCLCl9_Tjh-8CFQAAAAAdAAAAABAD
As we in Canada have been installing sidewall discharges with tradesman doing the work and they work well with little or no re-entrainment, and we use significantly less distances to building openings (12" min and 36" recommended) than you do in the USA.

I did my first field install yesterday in 1 1/2 years when we had a mitigator go out sick at last minute ........... my helper had been on 8 previous mitigations and he has completed the measurement training but not the mitigation training. It was obvious that he had not grasped the concepts of communication testing and what the numbers meant for fan sizing. It is not a concept that is easily teachable to many individuals but, it is critical to ensuring that the fan is rightsized for the building. Rightsizing the fans means that building air is not being stolen by SSD system that will cost the building owners 1000's of dollars over the next 5 -10 years.

Doug I agree with you. Reasonable Profit is not a dirty word. In Canada our pipe from the wholesaler is about 60-70$ per 12 foot length. but all of our fans ECT comes up from states and while there is a cost to crossing the border with materials with good management of this you can keep costs down. Our typical systems go for about 2160.00 US plus taxes or 3000.00 CAN. At that price point you are reinvesting most of profits in company to cover depreciation of capital assets and marketing to bring in new revenue streams. We routinely travel up to 5hrs drive (one way) to service new and repeat customers. To get down to the 1500.00 US I would be out of business. Maybe that is why 50% of US mitigators are in business for less than 2 years. The low price may be why mitigators are driven to install SDR 35 above grade inside the building, not do communication testing to properly size the fan, and alarm calls are a significant hassle.

great solution if it works looks clean and tidy you should look at the self regulating heating cable to provide a small pathway that would never freeze, it is a flat cable that hides well under insulation or could be drilled into exhaust pipe slid up pipe to top

Congratulations on getting this through it may be a step to getting a landlord requirement to test all rentals

Ok so as i understand the issue "standard does require insulation" within the building where could be exposed to freezing (ie the attic).
"Standard does require Alarms"
Alarms go off when pipe freezes customers call and complain when alarms go off
Alarms are that truly work are expensive. But they are expensive for all installers.
So the solution that best protects consumers is????
I do not believe that a complaint about the standard to the standard board is going to be successful.
one of my competitors slips 6" insulated duct around his pipes in attic it looks terrible but he says fast and cheaper and because no joints no possibility of sweating in summer, creating mold issues if you think a few calls about freezing are painful try being the cause of mold in an attic.

Running away from water issue we have had two tough houses starting at over 10,000 Bq/m3 or 270 pCi/l that refused to come down to below 100 because of compacted damp sand under slab we had 11 draw points on the system in one of the houses. To get the last i had to tap the block walls in 5 places (already had drop points right there ) we only discovered this when we drilled the block wall it blew the grab sampler at above 39,000 Bq/m3. We did connect restrictor plates inside piping to control amount of air drawn from block wall.

400 pCi/l is still can be a significant source depending what is going on with water usage i would look very hard at a 7 day electronic test and see if you are seeing hourly variance around water usage it typically takes a few hrs to show results after water usage on the device.

Let me start with I am very envious of the fact you have State Law that controls radon mitigators and what they do. I am tired of losing work to supposed mitigators who do not follow the rules, do not know what they are doing, are uncertified handyman, with no knowledge of building code, building envelope science, radiation protection (for their workers). They are taking money out of the pockets of my trained and certified employees and not serving our clients well (I get them as clients when radon mitigation doesn't work out)

So my questions to the group is do the current radon alarms Alarm when the radon system fails because it is cold outside, and let the homeowner know that they are being exposed to high levels of radon? From the comments i am hearing the answer is yes. So they are doing what they are supposed to! How do you change your business model to meet this new reality? Is this an opportunity profit more? Or is this a cost you must absorb driving profits down?

I am not sure from this discussion if you are more concerned about radon alarms or changing your business model to accommodate enforcement of the new rules.

Does the Ansi AARST document require insulation when piping is subject to freezing? Is this expensive and a tough upsell? My answer is maybe but i don't know your market. My market is concerned homeowners most are two income professionals who care about price tag but...... if we are doing a garage exhaust we highly recommend EPDM insulation and a self activating heat cable (if you scroll back i gave amazon link). If they do not buy it I don't send a radon tech out without them agreeing to pay for it.